1. Field of the Invention
The present invention relates generally to flow regulators, and, more particularly, but not by way of limitation, to flow regulators that incorporate a flow washer to maintain a desired flow rate over a greater range of fluid pressures.
2. Description of the Related Art
Flow regulators are used in many applications to control the flow rate of fluid through a conduit such that the flow rate of the fluid is uniform under varying pressure conditions. In many flow regulators, flow washers are incorporated for the purpose of maintaining flow rate. Flow washers are typically discs constructed of a flexible resilient material that have a central orifice extending therethrough. The central orifice of the flow washer distorts to different diameters under different pressure conditions. Specifically, the size of the diameter of the orifice reduces as the source pressure is elevated.
FIGS. 1 and 2 illustrate a flow washer 600 well known in the art. The flow washer 600 is designed to maintain a uniform flow rate after an initial threshold pressure is reached. In particular, fluid is allowed to pass through an orifice 601 of the flow washer until an initial threshold pressure is reached. After this initial threshold pressure is reached further pressure increases cause the flow washer 600 to deform reducing the diameter of the orifice 601. As illustrated in FIG. 2, further pressure increases after the initial threshold pressure deforms the flow washer 600 such that the orifice 601 is reduced in diameter, thereby maintaining a desired flow rate with the increase in pressure.
In many applications, flow washers are limited in their use because they can only regulate the flow rates of fluids over a limited range of pressures. For example, in a typical flow washer, the operating range of the flow washer with respect to pressure is limited, and, once the pressure increases beyond the operating range, the flow rate rapidly decreases. As illustrated in FIG. 3, as the pressure increases beyond the operating range, the diameter of the orifice reduces to a point where flow rate is rapidly decreased. What is desired in many applications is a flow washer that maintains the fluid flow rate more or less the same over a greater range of pressures.
Beverage dispensers are one application that requires the regulation of fluid flow rate over a range of pressures. In order for a beverage dispenser to create a proper tasting fountain drink, a beverage dispenser must maintain the correct water to syrup ratio. To achieve the proper water to syrup ratio, a beverage dispenser must regulate the flow rate of water and syrup. Maintaining the correct water to syrup ratio can be difficult to achieve for beverage dispensers. For example, water pressure varies depending upon location and also may be affected by the number of users dispensing a drink from a beverage dispenser. In order to achieve the correct water to syrup ratio regardless of water pressure, beverage dispensers use ceramic flow regulators employing a ceramic sleeve and piston. The ceramic flow regulators use a ceramic sleeve with side holes and a spring-loaded ceramic piston that moves and occludes the side holes in response to pressure changes. Beverage dispensers that employ ceramic flow regulators are effective in regulating flow of water and syrup over a given range of pressures to create a proper tasting dispensed beverage. However, ceramic flow regulators are expensive to manufacture. Replacing the ceramic flow regulator with a manual valve that uses a flow regulator incorporating a flow washer would be one way to control the costs of manufacturing a beverage-dispensing machine.
Accordingly, a flow regulator that incorporates a flow washer to maintain a desired fluid flow rate over a greater range of pressures would be useful. Furthermore, a beverage dispenser that integrates a flow regulator incorporating a flow washer would be an improvement in the beverage dispensing industry.